1. Field of the Invention
The present invention relates to a 2-aminothiazoline-4-carboxylate racemase gene, a recombinant DNA, a transformant or transductant, a 2-aminothiazoline-4-carboxylate racemase enzyme, a process for preparing the enzyme, and a process for preparing L-cysteine or L-cystine using the enzyme.
2. Prior Art
Bacteria belonging to the genus Pseudomonas are known as a representative of microorganisms converting DL-2-aminothiazoline-4-carboxylate, hereinafter abbreviated as DL-ATC, into L-cysteine (Japanese Patent Application Laid-open Publication No. 51-70881), and the cells thereof have hitherto used in the synthesis reactions of L-cysteine (Japanese Patent Publication No. 53-25037). Racemization of DL-ATC is required for efficient conversion of DL-ATC into L-cysteine and enzymatic racemization of DL-ATC is considered to take place in the above mentioned bacteria. However, these conventional bacteria only produce insufficient amounts of racemase and the efficiency of producing L-cysteine from starting DL-ATC is poor. Further, there has been no report on isolation of the above mentioned enzyme or the cloning of its gene.